Thermally actuated and thermally sealed valve

ABSTRACT

A thermally actuated and thermally sealed valve wherein a plug cock is a shrink fit within a casing, and the plug cock is urged in the operative direction by, say, a torsion spring or two electromagnets. Thermally expanding the casing and/or contracting the plug cock causes the casing to release the plug cock so that it is moved to either open or close the valve.

United States Patent 1 1 [111 3,782,681 Blackstein Jan. 1, 1974THERMALLY ACTUATED AND [56] References Cited THERMALLY SEALED VALVEUNITED STATES PATENTS [75] lnventor: Frederick Paul Blackstein, Chalk1,960,973 5/1934 Knight 137/65 River, Ontario, Canada 1,602,886 l0/l926Davis 3,048,190 8/l962 Carling [73] Assigncc: Atomic Energy of CanadaLimited, 2 337 33 3 9 3 Bolesky Ottawa, Ontario, Canada 2,572,27410/1951 Miller 251/66 X [22] Flled: May 1972 Primary Examiner-ArnoldRosenthal [21] Appl. No.: 250,873 Att0rney-Francis W. Lemon [30] ForeignApplication Priority Data [57] ABSTRACT Au 1 l 1971 Canada 120299 Athermally actuated and thermally sealed valve wherein a plug cock is ashrink fit within a casing, and [52] U s C] 251/11 25l/66 137/457 theplug cock is urged in the operative direction by, 236/90 236/68 say, atorsion spring or two electromagnets. Thermally [51] Int Cl [16k 31/02expanding the casing and/or contracting the plug cock [58] Field415515111III""IIIiIiIIII'I1551/66 68 11 causes the casing to release thePlug that it is moved to either open or close the valve.

5 Claims, 2 Drawing Figures THERMALLY ACTUATED AND THERMALLY SEALEDVALVE This invention relates to a thermally actuated and thermallysealed valve.

In some instances it is necessary to provide a leaktight, reliable, andtamper-proof valve, which is unlikely to be inadvertently opened orclosed. It is preferable for such a valve to be of simple constructionand easily maintained, by virtue or few moving parts and a fundamentalsealing mechanism.

It is an object of the present invention to provide a substantiallyleaktight, reliable, tamper-proof, thermally actuated and thermallysealed valve, which is unlikely to be inadvertently opened or closed andwhich is of simple construction and easily maintained by virtue of fewmoving parts and a fundamental sealing mechanism.

In other instances it is necessary for a valve to be actuated to open orclose the valve by, for example, a change in the temperature of thefluid whose flow is controlled by the valve.

It is another object of the present invention to provide a valve whichis actuated to open or close the valve by a change in the temperature ofthe fluid whose flow is controlled by the valve.

According to the present invention there is provided a thermallyactuated and thermally sealed valve, comprising a casing, a plug cock ata first operative position within the casing and held substantiallyagainst leakage and movement by an interference fit with the casing, andactuating means urging the plug cock from the first operative positionto a second operative position, whereby differential thermal expansionor contraction between the casing and plug cock releases the plug cockfor movement by the actuating means to the second operative position.

In the accompanying drawings which illustrate, by way of example,embodiments of the present invention,

FIG. 1 is a partly sectioned side view of a thermally actuated andthermally sealed valve,

FIG. 2 is a partly sectioned side view of a different thermally actuatedvalve.

Referring to FIG. 1 there is shown a thermally actuated and thermallysealed valve, comprising a casing l, a plug cock 2 at a first operativeposition within the easing 1 and hold against movement and leakage by aninterference fit with the casing 1. An actuating means in the form of atorsion spring 4 urges the plug cock 2 from the first operative positionto a second operative position, whereby differential thermal expansionor contraction between the casing 1 and plug cock 2 releases the plugcock 2 for movement by the torsion spring 4 to the second operativeposition.

The casing 1 has an inlet 6 and an outlet 8, and a cap 10 closes a topportion of the casing 1. The cap 10 is secured to the casing 1 by aplurality of bolts, one of which is shown and designated 12. A seal 14is disposed in a groove 16 and seals the plug cock 2 to the casing 1during the operative phase. An electrical heating coil 18 is disposedaround the casing l.

The plug cock 2 is mounted in the casing 1 between bearings 20 and 22,and a pin 24 is secured in the casing 1 and is slidable in an arcuateslot 26 in the plug cock 2 to restrict rotational motion of the plugcock 2 about the longitudinal axis to 90 to position, as will bedescribed later, a bore 28 in the plug cock 2 in alignment with theinlet 6 and outlet 8.

The upper end of the plug cock 2 has a spindle 30 extending through anopening 32 in the cap 10 and having a collar 34 welded thereon. Thetorsion spring 4 has one end secured to the cap 10 and the other endsecured to the collar 34 and urges the plug cock 2 in the direction ofarrow X.

The valve is assembled with the plug cock 2 in the first operativeposition as shown in FIG. 1 by heating the casing 1 and cooling the plugcock 2 so that the plug cock 2 will slide in to the casing 1. The casing1 and plug cock 2 are then allowed to attain equilibrium temperaturewith the plug cock 2 in the position shown in FIG. 1. As the casing 1and the plug cock 2 attain equilibrium temperature, the casing 1contracts and the plug cock 2 expands so that the plug cock 2 is lockedin the casing 1 against leakage and rotational movement (in thedirection of arrow X) by the interference fit between the casing l andthe plug cock 2.

The cap 10 is then rotated in the opposite direction to arrow X to windup the coils of the torsion spring 4 and apply the desired torsionbetween the cap 10 and the collar 34. The cap 10 is then bolted to thecasing l. The valve is then ready for use.

In operation, when it is required to actuate the valve to move the plugcock 2 to the second operative position this is done thermally byheating the casing l by the electrical heating coil 18 until the casingl is loosened from the plug cock 2. When the casing 1 is loosened fromthe plug cock 2, the plug cock 2 is automatically rotated in thedirection of arrow X by the torsion spring 4 until the bore 28 isaligned with the inlet 6 and the outlet 8. Further rotational movementof the plug cock 2 is prevented by the pin 24 having moved the fullsweep of the arcuate slot 26. Thus the valve has been thermally actuatedto be opened by the electrical heating coil 18 and thermally sealed byvirtue of the interference fit at the equilibrium condition.

As an example using a steel plug cock 2 having a 1.00 inch diameterbefore assembled, the casing 1 may also be of steel and have an internaldiameter of 0.9995 inches before assembled. By heating the casing l and-/or cooling the plug cock 2 to create a temperature differential betweenthem of lO0F the plug cock 2 will become a loose fit in the casing l foreither assembly or actuation.

It will be appreciated that it is within the scope of the presentinvention for a valve to be thermally actuated to close the valve andsimilarly sealed in the closed position.

It is also within the scope of the present invention to cool the plugcock 2 to thermally actuate the valve.

The simplicity of valves according to the present invention enhancestheir reliability and ease of maintenance. As the valve can only bythermally actuated it may in some embodiments be actuated by changes inthe temperature of the fluid whose flow is being controlled by thevalve. This can be achieved by making the casing l and plug cock 2 ofdissimilar metals such that for the same temperature change the plugcock 2 will become loosened within the casing 1, that is, the casing 1may be expanded away from the plug cock 2, or the plug cock 2 may becontracted away from the casing 1.

In different embodiments the casing 1 may, as already stated, have adifferent coefficient of linear expansion than the plug cock 2, or thevalve stem 1 and plug cock 2 may have different rates of thermalconductivity.

Valves of the present invention are particularly useful in areas whereonly intermittent use of the valve is required, more particularly whenthe valve is remotely located and is, for example, for shut-downpurposes in emergency.

It will be noted that the plug cock 2 preferably has an upper portion 36of smaller diameter than the lower portion to reduce thermalconductivity between the casing l and the plug cock 2.

In FIG. 2 parts similar to those shown in FIG. 1 are designated by thesame reference numerals, and the previous description is relied upon todescribe them.

The valve shown in FIG. 2 has a permanent magnet 38 mounted on thespindle 30 locked therewith. The magnet 38 has the poles disposed asindicated. Two electromagnets 40 and 42 are mounted on the cap bybrackets 44 and 46 respectively. The windings of the electromagnets 40and 42 are connected to a dc power source 48 through a reversing switch50.

The valve is assembled in the same manner as the valve shown in FIG. 1,except that during assembly the reversing switch 50 is set to energisethe electromagnets so that they each attract the pole of the permanentmagnet 30 that is nearest to them. This electromagnet 40 attracts thenorth pole and electromagnet 42 attracts the south pole. When the plugcock 2 has been locked in the casing 1 in the manner described withreference to FIG. 1, the reversing switch 50 is then set so that theelectromagnets 40 and 42 repel the north and south poles respectively ofthe permanent magnet 38 and urge the plug cock 2 to rotate in thedirection of arrow X. In order to urge the plug cock 2 to rotate in thedirection of arrow X the electromagnets 40 and 42 are set slightly backfrom the permanent magnet 38 in the reverse direction to arrow X.

In operation the valve operates in the same manner as the valve shown inFIG. 1 except that the plug cock 2 is rotated by the electromagnets 40and 42.

I claim:

1. A thermally actuated and thermally sealed valve, comprising a casing,a plug cock within the casing and mounted for movement therein betweentwo operative positions at which the valve is open and closed and heldsubstantially against said movement and leakage between the plug cockand the casing by an interference fit between the plug cock and thecasing, and actuating means urging the plug cock from a first of theoperative positions to a second of the operative positions, wherebydifferential thermal expansion or contraction between the casing andplug cock causes the plug cock to become a loose fit in the casing andreleases the plug cock for movement by the actuating means to the secondoperative position.

2. A valve according to claim 1 wherein the means urging the plug cockfrom the first operative position to the second operative positioncomprises a torsion spring having one end secured to the casing and theother end secured to the plug cock, the plug cock is cylindrical and thetorsion spring urges the plug cock to rotate within the casing to thesecond operative position, bearing means mount the plug cock for therotational movement within the casing, and a seal seals the plug cock tothe casing.

3. A valve according to claim 2, wherein the plug cock has a bore whichis aligned with a fluid inlet and a fluid outlet in the casing in thesecond operative position.

'4. A valve according to claim 1, comprising an electrical heating coilaround the casing for heating the easing to thermally operate the valve.

5. A valve according to claim 1 wherein the actuating means urging theplug cock from the first operative position to the second operativeposition comprises an electromagnet, the plug cock is cylindrical andthe electromagnet urges the plug cock to rotate within the casing to thesecond operative position, bearing means mount the plug cock for therotational movement within the casing, and a seal seals the plug cock tothe casing.

1. A thermally actuated and thermally sealed valve, comprising a casing,a plug cock within the casing and mounted for movement therein betweentwo operative positions at which the valve is open and closed and heldsubstantially against said movement and leakage between the plug cockand the casing by an interference fit between the plug cock and thecasing, and actuating means urging the plug cock from a first of theoperative positions to a second of the operative positions, wherebydifferential thermal expansion or contraction between the casing andplug cock causes the plug cock to become a loose fit in the casing andreleases the plug cock for movement by the actuating means to the secondoperative position.
 2. A valve according to claim 1 wherein the meansurging the plug cock from the first operative position to the secondoperative position comprises a torsion spring having one end secured tothe casing and the other end secured to the plug cock, the plug cock iscylindrical and the torsion spring urges the plug cock to rotate withinthe casing to the second operative position, bearing means mount theplug cock for the rotational movement within the casing, and a sealseals the plug cock to the casing.
 3. A valve according to claim 2,wherein the plug cock has a bore which is aligned with a fluid inlet anda fluid outlet in the casing in the second operative position.
 4. Avalve according to claim 1, comprising an electrical heating coil aroundthe casing for heating the casing to thermally operate the valve.
 5. Avalve according to claim 1 wherein the actuating means urging the plugcock from the first operative position to the second operative positioncomprises an electromagnet, the plug cock is cylindrical and theelectromagnet urges the plug cock to rotate within the casing to thesecond operative position, bearing means mount the plug cock for therotational movement within the casing, and a seal seals the plug cock tothe casing.